I've yet to get around to attempting my own, but initially my aim was probably focused on getting perfect edge to edge coverage with even exposure and development. [And hopefully interesting composition, but lets be reasonable with the goals here...]
After studying other photographer's work and people's reaction to them, I am however considering shifting the concept of my goal to something more along the lines of a perfect central coat, with a deliberate incomplete edge coverage. A truly 'perfect' hand coated plate, wet or dry, seems to be hard for many in the public to really appreciate while being able to tell it apart from modern mass production methods.
Under coating the surface, and letting the edges 'lie as they will' with an inconsistent 'natural' pattern, seems to offer a more immediate and visual connection with something having been done by hand.
Possibly something to do with so many of the public being so far removed from making anything for themselves that some can't really comprehend the level of detail and precision a human is able to achieve on their own?